Smart surgical instruments for artificial joint replacement

ABSTRACT

A smart surgical instrument for artificial joint replacement includes a femur resection device, a tibia resection device, and a detector having a shape corresponding to the resected surfaces of a femur and a tibia. The femur resection device includes a laser device such that the femur resection device can be aligned for resection of the femur without drilling an intramedullary hole, thereby preventing complications attributable to the intramedullary hole. The tibia resection device includes a laser device, thereby enabling an easy and fast surgical operation without using an extramedullary aligner used for alignment of a tibia during resection of the tibia. The detector includes a rotation detection means and a pressure detection means and is inserted between trials to allow numerical verification for medial and lateral balance of forces and a rotation state of the trials. The surgical instrument enables a precise, accurate, easy, and fast surgical operation.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a divisional of U.S. application Ser. No.15/818,342, filed Nov. 20, 2017, which claims priority to Korean PatentApplication No. 10-2017-0107078, filed Aug. 24, 2017, the entirecontents of which are incorporated herein for all purposes by thisreference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates generally to a smart surgical instrumentfor artificial joint replacement. More particularly, the presentinvention relates to a smart surgical instrument for artificial jointreplacement, the smart surgical instrument including a femur resectiondevice for resecting a femur, a tibia resection device for resecting atibia, and a detector having a shape corresponding to the resectedsurfaces of the femur and the tibia, in which: the femur resectiondevice includes a laser device which eliminates the need of drilling anintramedullary hole for alignment of the femur during femur resection,thereby preventing complications; the tibia resection device includes alaser device which eliminates the need of using an extramedullaryaligner for tibia resection, thereby enabling an easy and fast surgicaloperation; and the detector includes a rotation detection means and apressure detection means disposed between trials, thereby enablingnumerical verification for balance of forces and a rotation state ofcomponents, which enables a precise, accurate, easy, and fast surgicaloperation.

Description of the Related Art

The knee joint is an articulation that joins a tibia and a femur. Whenthe knee joint cannot properly function for reasons such as being wornor damaged, it is replaced with an implant (i.e. artificial joint)through a knee replacement surgery known as knee arthroplasty.

Knee arthroplasty is a complex surgical procedure requiring a highlyprecise and skilled surgical technique. An implant used in the kneearthroplasty is mainly composed of a tibial component, a femoralcomponent, and an insert being interposed between the tibial componentand the femoral component and functioning like a bearing.

To implant the tibial component and the femoral component, a proximalend of a tibia and a distal end of a femur need to be resected bypredetermined amounts. Since stability and mobility of the artificialknee joint depend on the inclination angles of the resected surfaces andthe resection amounts of the femur and tibia, resecting the end portionsof the femur and tibia needs to be highly precisely performed.Accordingly, alignment parts (cutting guide portions) need to be used toguide resection surfaces of the tibia and the femur.

The invention disclosed in Patent document discloses a guide assemblyfor guiding a cutting device that cuts away a distal end of a femur anda proximal end of a tibia during a knee arthroplasty. This technologyuses a method of drilling deep holes in the femur and the tibia andinserting intramedullary rods (IM rods) into the holes for alignment ofthe femur and the tibia.

However, drilling deep holes for insertion of the IM rods as in theconventional technology may cause various complications. For example,bone cells in the holes are damaged or may be infected by bacteria, or afat embolism in which fatty matter flows into a vein to block the flowof blood may occur due to damage of bone marrow. In addition, thedrilling also requires strong force and increases the number of toolsfor a surgical operation, which complicates the surgical procedure andlengthens the operation time with which a surgeon is burdened.

As illustrated in FIG. 1, according to the conventional technology, ahole H is drilled in a femur 91 using a drill D so that anintramedullary rod (IM rod) can be inserted into the hole H. FIG. 2illustrates a surgical instrument with a large knob A used to insert theintramedullary rod into the hole H. The axial alignment techniqueinvolving the drilling is disadvantageous in terms of complicatedoperation processes and low space utilization efficiency due to the factthat a number of surgical instruments having a large size are used.

As to resection of a tibia, as illustrated in FIG. 3, an extramedullaryalignment member J extending from a proximal end 931 to a distal end 933of a tibia is used for axial alignment of the tibia. The alignmentmember J has a larger volume than the tibia 93. Therefore, a surgicaloperation using the alignment member J is complicated and takes a longtime. The complicated procedure and lengthened operation time negativelyaffect a patient's health and burden surgeons.

With reference to FIG. 4, after the distal end 913 of the femur and theproximal end 931 of the tibia are resected, whether the femur and thetibia are properly resected is verified with a balance checker 5′.Alternatively, after trials having the same shape as implants(prostheses) are attached to the resected surfaces, the respectedsurfaces are verified with the balance checker 5′. The tibia 93 isflexed or extended with respect to the femur 91 and a gap between thefemur 91 and the tibia 93 is checked. As a result, the distal end 913 ofthe femur 91 or the proximal end 931 of the tibia 93 is further resectedor the implants are replaced with new ones having a different size inaccordance with the verification results.

The balance checker 5′ used in the conventional technology has a problemof providing imprecise verification results because such a verificationis only visually performed by eye. Therefore, the accuracy ofverification results largely relies on experience and sensation of asurgeon. With reference to FIG. 4, an alignment member J′ is attached toone side of the balance checker 5′ for alignment of the balance checker5′. Since the alignment member J′ has a large volume and an installationtime thereof is long, it is likely to burden a surgeon and to negativelyaffect a patient's health.

Therefore, surgical instruments for artificial joint replacement, whichcan easily and rapidly align cutting guide portions and have reducedsizes, are needed to enable an effective surgical operation duringreplacement of an artificial joint. Furthermore, the surgicalinstruments need to be equipped with a function of precisely and easilyverifying medial and lateral force balance after resection of bones.

DOCUMENT OF RELATED ART Patent Document

-   Korean Patent No. 10-1612332 (registered as of Apr. 7, 2016) “Guide    Assembly For Guiding Cuts To A Femur And Tibia During A Knee    Arthroplasty”

SUMMARY OF THE INVENTION

Accordingly, the present invention has been made keeping in mind theabove problems occurring in the related art, and an objective of thepresent invention is to provide a smart surgical instrument for anartificial joint replacement, the instrument being beneficial to apatient's health and being capable of reducing a surgeon's burden byeasily and rapidly aligning components of the surgical instrument byusing a laser device.

Another objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument beingcapable of preventing bone cells from being damaged or infected withbacteria and preventing complications such as a fat embolism byeliminating a process of drilling an intramedullary hole in a femur byaligning a femur resection device using a laser device.

A further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument beingequipped with no additional device having a large volume because italigns a femur resection device for resecting a femur using a laserdevice, thereby simplifying and speeding up a surgical operationprocess, which alleviates a burden to both a surgeon and a patient.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument beingequipped with two laser devices for alignment of a femur, therebyenabling easy and quick verification for alignment of a femur resectiondevice both on a coronal plane and a sagittal plane during alignment ofa femur, which alleviates a burden to a surgeon and enables a preciseand accurate alignment.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument beingequipped with a rotation detection means in a femur resection device,thereby enabling numerical verification for a rotation state of a fixingportion, which alleviates a burden to a surgeon and enables an easyoperation and a precise and accurate alignment.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument aligninga tibia resection device for resection of a tibia using a laser beam,thereby improving space utilization efficiency and reducing a burden toa surgeon and a patient by not using an additional extramedullaryaligner for alignment of the tibia.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument includinga tibia resection device equipped with a rotation detection means,thereby enabling precise numerical verification for an alignment stateof a tibia cutting guide portion during alignment of the tibia cuttingguide portion, which reduces a mental burden to a surgeon and enables aneasy operation and a precise and accurate alignment.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument includinga detector having a shape corresponding to that of the resected surfaceof a tibia, in which the detector includes a rotation detection means,thereby providing precise numerical verification for a rotation state ofan implant during alignment of the implant, which reduces a mentalburden to a surgeon and enables an easy operation and a precise andaccurate alignment.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument includinga detector equipped with a pressure detection means, thereby enablingprecise numerical verification for medial and lateral balance andpressure distribution of an implant, which reduces a burden to a surgeonand enables an easy operation and a precise and accurate alignment.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument includinga detector having a knob means so that the detector can be easilyinstalled and removed by holding the knob means.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument includinga balance checker mounted with a detector, in which the balance checkerincludes a laser device which enables verification for axial alignmentwith a laser beam during balance checking, which enables a fast and easyoperation.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument charginga battery of a detector in an wireless manner, thereby enabling an easy,simple, and fast operation.

A yet further objective of the invention is to provide a smart surgicalinstrument for an artificial joint replacement, the instrument having astructure in which a battery and a detector are detachably combined witheach other so that the battery can be conveniently charged.

In order to accomplish the above object, the present invention isimplemented by embodiments having the structures described below.

According to one embodiment of the present invention, there is provideda smart surgical instrument for an artificial joint replacement, thesurgical instrument including a laser device, thereby easily andconveniently performing alignment of components thereof by using thelaser device.

According to another embodiment of the present invention, the surgicalinstrument may further include a femur resection device for resecting afemur, wherein the femur resection device includes a laser device,thereby eliminating a process of drilling an intramedullary hole foralignment of the femur during resection of the femur, thereby preventingcomplications attributable to drilling the intramedullary hole.

According to a further embodiment of the present invention, the femurresection device may include: a fixing portion attached to a distal endof the femur; a cutting guide portion aligned with respect to the fixingportion; and a connecting portion connected to one side of the fixingportion, in which the connecting portion comprises a laser devicealigning the fixing portion using a laser beam emitted by the laserdevice, thereby enabling an easy and convenient surgical operation.

According to a yet further embodiment of the present invention, theconnecting portion may include an ML laser device emitting a laser beamtoward a proximal end of the femur from a front side of the femur and anAP laser device emitting a laser beam toward the proximal end of thefemur from a medial side or a lateral side of the femur, therebyfacilitating alignment of the fixing portion in a medial-lateraldirection and a an anterior-posterior direction.

According to a yet further embodiment of the present invention, theconnecting portion may include an ML member extending in themedial-lateral direction and an AP member extending in theanterior-posterior direction, and the ML member and the AP memberrespectively include the ML laser device and the AP laser device,thereby facilitating alignment of the fixing portion in themedial-lateral direction and the anterior-posterior direction.

According to a yet further embodiment of the present invention, thecutting guide portion may include a frontal cutting guide portion thatguides cutting of a frontal portion of the distal end of the femur and adistal cutting guide portion that guides cutting of a middle portion ofthe distal end of the femur, and the distal cutting guide portion may bealigned by being connected to the fixing portion via the frontal cuttingguide portion.

According to a yet further embodiment of the present invention, thefixing portion may include a rotation detection means that enablesnumerical verification for a rotation state of the fixing portion duringalignment of the fixing portion, which is performed by using a laserbeam, thereby facilitating precise, accurate, and fast alignment of thefixing portion and enabling an accurate surgical operation by preventingthe fixing portion from being displaced after the fixing portion isaligned.

According to a yet further embodiment of the present invention, therotation detection means may be a gyro sensor.

According to a yet further embodiment of the present invention, thesurgical instrument may further include a tibia resection device forresecting a tibia, in which the tibia resection device includes a laserdevice, whereby the surgical instrument enables an easy and fastsurgical operation by eliminating the need of using an extramedullaryaligner during alignment of the tibia for resection of the tibia

According to a yet further embodiment of the present invention, in thesurgical instrument, the tibia resection device may include a tibiacutting guide portion attached to a frontal end of the tibia and aconnector combined with the tibia cutting guide portion, and theconnector may include a laser device emitting a laser beam to a distalend of the tibia, whereby the surgical instrument facilitates alignmentof the tibia cutting guide portion.

According to a yet further embodiment of the present invention, in thesurgical instrument, the tibia cutting guide portion may include arotation detection means, thereby enabling numerical verification for analignment state of the tibia cutting guide portion when the tibiacutting guide portion is aligned with a laser beam, whereby the surgicalinstrument enables precise, accurate, easy, and fast alignment of thetibia cutting guide portion.

According to a yet further embodiment of the present invention, there isprovide a surgical instrument for artificial joint replacement, thesurgical instrument including a rotation detection means, therebyenabling a precise, accurate, and easy surgical operation by numericallyprecisely controlling a resection position of a bone and an installationposition of an implant.

According to a yet further embodiment of the present invention, thesurgical instrument may further include: a reference rotation detectionmeans providing a reference position used to detect a rotation angle ofa component of the surgical instrument; and an operation rotationdetection means detecting the rotation angle of the component withrespect to the reference rotation detection means.

According to a yet further embodiment of the present invention, thesurgical instrument may further include a detector having a shapecorresponding to a tibial component trial and a resected surface of thetibia, in which the detector includes an operation rotation detectionmeans and a pressure detection means and is inserted between the tibialcomponent trial and an insert trial, thereby enabling an easy and fastsurgical operation by allowing numeral verification for medial andlateral balance and for a rotation degree of the trials.

According to a yet further embodiment of the present invention, thedetector may be provided with a positioning recess in one surfacethereof, and the tibial component trial may be provided with apositioning protrusion at one surface thereof to position the detector,in which the detector has the positioning recess at a positioncorresponding to the positioning protrusion so that the detector ispromptly and easily positioned on the tibial component trial and isprevented from slipping after being placed on the tibial componenttrial.

According to a yet further embodiment of the present invention, thesurgical instrument may include a femoral component trial and a balancechecker inserted between the tibia and the femur to check medial andlateral balance, in which the balance checker includes a detector havingthe a shape corresponding to the resected surface of the tibia, and thedetector includes an operation rotation detection means and a pressuredetection means to allow numerical verification for medial and lateralbalance and a rotation state when the balance checker is insertedbetween the tibia and the femur, thereby enabling an easy and fastsurgical operation.

According to a yet further embodiment of the present invention, thebalance checker may include a first insertion portion provided with anaccommodation recess in which the detector is accommodated, the detectormay be provided with a knob means at a periphery portion thereof, andthe accommodation recess may be provided with an outer recess at aposition corresponding to the knob means such that the detector iseasily removable from the balance checker.

According to a yet further embodiment of the present invention, thebalance checker may include a second insertion portion composed of anupper plate and a lower plate such that the detector is inserted betweenthe upper plate and the lower plate, whereby the detector is insertedinto and removed from the balance checker in a sliding manner.

According to a yet further embodiment of the present invention, thebalance checker may be equipped with a laser device at one side thereof,thereby allowing easy verification for an alignment state of the balancechecker.

According to a yet further embodiment of the present invention, thedetector may be equipped with a battery for supplying power to operatethe operation rotation detection means and the pressure detection means,and the battery may be charged through a wireless charging method.

According to a yet further embodiment of the present invention, thebattery may be detachably mounted in the detector.

According to the present invention, it is possible to obtain advantagesdescribed below due to the preferred embodiments, the structures to bedescribed below, and combinations and applications of the embodiments orstructures.

According to the present invention, since a surgical instrument includesa laser device, it is possible to easily and promptly align componentsof the instrument, thereby reducing a burden to a surgeon and providingeffects advantageous for recovery of a patient.

According to the present invention, since the surgical instrument alignsa femur resection device for resecting a femur with a laser beam, it isnot necessary to drill an intramedullary hole in the femur, therebypreventing bone cells from being damaged and thereby minimizingcomplications such as infection or a fat embolism.

According to the present invention, since the surgical instrument alignsa femur resection device for resecting a femur with a laser beam, it isnot necessary to use additional devices having large sizes. Therefore,an operation process is simplified and sped up, which is advantageousfor recovery of a patient and reduces a burden to a surgeon.

According to the present invention, since the surgical instrument usestwo laser devices during alignment of a femur, a coronal plane alignmentand a sagittal plane alignment can be easily and promptly performed.Therefore, a burden to a surgeon is reduced, and a precise and accuratealignment is possible.

In addition, since the femur resection device includes a rotationdetection means, the rotation state of a fixing portion can be verifiedwith a specific numerical value, which reduces a burden to a surgeon,facilitates a surgical operation, and enables an easy, precise, andaccurate alignment.

In addition, since a tibia resection device for resecting a tibia isaligned with a laser beam, it is not necessary to use an additionalextramedullary aligner, which improves space utilization efficiency andspeeds up a surgical operation, thereby reducing a burden to a surgeonand being advantageous for recovery of a patient.

In addition, since the tibia resection device includes a rotationdetection means that enables numerical verification for an alignmentstate of the tibia resection device, a burden to a surgeon is reduced, asurgical operation is facilitated, and a precise and accurate alignmentis possible.

In addition, the surgical instrument includes a detector having a shapecorresponding to that of the resected surface of the tibia, and thedetector includes a rotation detection means. Therefore, a rotationstate of an implant can be precisely verified with a specific numericalvalue during alignment of an implant. Thus, a burden to a surgeon isreduced, a surgical operation is facilitated, and a precise and accuratealignment is possible.

In addition, the detector includes a pressure detection means.Therefore, medial and lateral force balance and pressure distributioncan be precisely verified with specific numerical values. Thus, a burdento a surgeon is reduced, a surgical operation is facilitated, and aprecise and accurate alignment is possible.

In addition, the detector has a knob means to be held for movement.Therefore, the detector can be easily installed and removed by holdingthe knob means.

In addition, the surgical instrument includes a balance checker in whichthe detector is accommodated, and the balance checker includes a laserdevice. Therefore, axial alignment of an implant is verified duringverification for balance using a laser beam, which enables an easy andfast surgical operation.

In addition, since a battery in the detector can be charged in awireless charging manner, an operation can be conveniently performed ina short time.

In addition, since the battery is detachably mounted in the detector,the battery can be conveniently charged.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description when taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view illustrating a state in which a hole isdrilled in a femur such that an intramedullary rod (IM rod) can beinserted into the hole of the femur, according to a conventional art;

FIG. 2 is a perspective view illustrating a state in which variouscomponents of a surgical instrument are arranged to resect a portion ofthe femur after the intramedullary rod is inserted into the hole of thefemur, according to the conventional art;

FIG. 3 is a side view illustrating a state in which a cutting guideportion is aligned using an extramedullary alignment member to resect aportion of a tibia, according to the conventional art;

FIG. 4 is a side view illustrating a state in which axial alignment isverified using an additional alignment member during verification ofbalance which is performed with a balance checker, according to theconventional art;

FIG. 5 is a perspective view illustrating a state in which a fixingportion is attached to a femur, according to one embodiment of thepresent invention;

FIG. 6 is a perspective view illustrating principles of connecting aconnecting portion to the fixing portion according to one embodiment ofthe present invention;

FIG. 7 is a side view illustrating a process of aligning the axis of afemur using a laser beam according to one embodiment of the presentinvention;

FIG. 8 is a front view illustrating the process of aligning the axis ofthe femur using the laser beam according to one embodiment of thepresent invention;

FIG. 9 is a perspective view illustrating a process of combining acutting guide portion with the fixing portion according to oneembodiment of the present invention;

FIG. 10 is a front view illustrating a process of attaching a tibiaresection device to a tibia and aligning the tibia resection device withthe axis of the tibia using a laser beam according to one embodiment ofthe present invention;

FIG. 11 is a side view illustrating a side view illustrating the processof attaching the tibia resection device to the tibia and aligning thetibia resection device with the axis of the tibia using the laser beamaccording to one embodiment of the present invention;

FIG. 12 is a side view illustrating a state in which the balance checkeraccording to one embodiment of the present invention is inserted and theknee joint is flexed;

FIG. 13 is a side view illustrating a state in which the knee joint inwhich the balance checker is mounted is extended;

FIG. 14 is an exploded perspective view illustrating the balance checkerand a detector according to one embodiment of the present invention;

FIG. 15 is an exploded perspective view illustrating a balance checkerand a detector according to another embodiment of the present invention;

FIG. 16 is an exploded perspective view illustrating a trial and thedetector according to one embodiment of the present invention;

FIG. 17 is an exploded perspective view illustrating an insert trial andthe detector according to one embodiment of the present invention;

FIG. 18 is a bottom exploded perspective view illustrating the trial andthe detector according to one embodiment of the present invention;

FIG. 19 is a perspective view illustrating a process of verifyingbalance using the trial and the detector in a state in a knee joint isextended, according to one embodiment of the present invention;

FIG. 20 is a perspective view illustrating a process of verifyingbalance using the trial and the detector in a state in which a kneejoint is flexed, according to one embodiment of the present invention;

FIG. 21 is a perspective view illustrating a process of charging of thebattery using a whole detector mounted with battery which is placed oncharging means according to one embodiment of the present invention; and

FIG. 22 is a perspective view illustrating a process of charging ofbattery using battery which is placed on charging means according toanother embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinbelow, a surgical instrument for artificial joint replacementaccording to the present invention will be described with reference tothe accompanying drawings. Like reference numbers refer to like elementsthroughout the drawings. Detailed descriptions of known functions andconfigurations which have been deemed to obscure the gist of the presentinvention will be omitted below. Unless otherwise defined, all termsincluding technical and scientific terms used herein have the samemeaning as commonly understood by one of ordinary skill in the art towhich this invention belongs. It will be further understood that terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and the present disclosure, and will notbe interpreted in an idealized or overly formal sense unless expresslyso defined herein.

Next, a surgical instrument for artificial joint replacement will bedescribed in detail with reference to the accompanying drawings.

With reference to FIGS. 6, 11, 12, and 17, according to one embodimentof the present invention, a surgical instrument S includes a femurresection device 1, a tibia resection device 3, a detector 8, a balancechecker 5, and a trial 7.

With reference to FIGS. 5, 6, and 9, the femur resection device 1includes a fixing portion 11 attached to a distal end 913 of a femur 91,a connecting portion connected to the fixing portion 11, a frontalcutting guide portion 13 connected to the fixing portion 11, and adistal cutting guide portion 15 connected to the frontal cutting guideportion 13.

With reference to FIG. 5, the fixing portion 11 which is a component foraligning the cutting guide portions 13 and 15 with respect the femur 91is attached to the distal end 913 of the femur 91. The fixing portion 11includes a distal fixation hole 111 to be engaged with the distal end913 of the femur 91, a first connection hole 113 to be engaged with thefrontal cutting guide portion 13 and the connecting portion 17, a firstlocking means 115 for locking a member inserted into the firstconnection hole 113, and a fixing portion rotation detection means 117for detecting a rotation state of the fixing portion 11.

The distal fixation hole 111 is a hole through which a fixing portionfixing means 112 used to attach the fixing portion 11 to the distal end913 of the femur 91 is inserted. The distal fixation hole 11 is composedof a distal center fixation hole 1111 disposed at a center portion ofthe fixing portion, a distal lopsided elongated hole 1113 disposed atone side of the fixing portion and elongated in a vertical direction,and a distal lopsided fixation hole 1114 disposed at the opposite sideof the distal lopsided elongated hole 1113 and having a circular shape.

The first connection hole 113 is a hole extending through the fixingportion 11 in an anterior-posterior direction. A first connection member131 of the frontal cutting guide portion 13 or a connection member 173of the connecting portion 17 is selectively inserted into the firstconnection hole 113. The first locking means 115 is a component forsecurely fixing the first connection member 131 or the connection member173 inserted into the first connection hole 113 in a screw-lockingmanner.

The fixing portion rotation detection means 117 is structured to detecta numerical value of the axial alignment state when the fixing portion11 is attached to the distal end 913 of the femur 91. The fixing portionrotation detection means 117 may be a sensor that detects a rotationangle by measuring an angular speed or an angular acceleration.Preferably, the fixing portion rotation detection means 117 may be agyro sensor. Since the rotation state of the fixing portion 11 isdetected by the rotation detection means 117, when the fixing portion 11is aligned using laser devices (denoted by reference numbers 1759 and1773 in FIG. 6), which will be described below, it is possible to verifythe rotation state of the fixing portion 11 with a numerical valueduring alignment of the fixing portion 11. Therefore, a precise andaccurate alignment is possible, which reduces a surgeon's stress. Inaddition, it is possible to detect a displacement of the fixing portion11 after the alignment of the fixing portion 11 is performed once.Therefore, a precise and accurate resection of the femur is possible.The fixing portion rotation detection means 117 needs to detect arotation angle of the fixing portion with respect to the femur 91.Therefore, it is preferable that an additional rotation detection meansis installed on the femur 91.

The rotation detection means 117 may further include a communicationdevice to send the rotation state of the fixing portion 11 to anexternal display device. Therefore, the rotation state of the fixingportion 11 can be verified using the external display device. The fixingportion 11 is a small device. Therefore, it is difficult for a surgeonto precisely observe the state of the fixing portion 11 when it isinstalled on a small surgical area. For this reason, when the fixingportion 11 communicates with the external display device, the surgeoncan clearly observe the rotation state of the fixing portion 11 due toan enlarged image or numerical information displayed on the externaldisplay device. Therefore, the surgeon can easily, precisely, andaccurately align the fixing portion with respect to the femur.

With reference to FIG. 6, the connecting portion 17 is a component usedto connect a laser device to the fixing portion for fast and easyalignment of the fixing portion 11. The connecting portion 17 includes aconnection hole insertion member 171 to be inserted into the firstconnection hole 113, the connection member 173 extending from one sideof the connection hole insertion member 171 at a predetermined angle, anML member 175 connected to the connection member 173 and extending in amedial-lateral direction, and an AP member 177 connected to a portion ofthe ML member 175 and extending in the anterior-posterior direction.

The connection hole insertion member 171 is a component that is insertedinto the first connection hole 113 of the fixing portion 11 to securelyfix the connecting portion 17 at a predetermined position. Preferably,there are two connection hole insertion members 171, thereby preventingthe connecting portion 17 connected to the fixing portion 11 from beingaxially rotated.

The connection member 173 is a component that connects the connectionhole insertion member 171 and the ML member 175 to each other. Theconnection member 173 includes a first connection member 1731 extendingin a proximal-distal direction of the femur 91 and a second connectionmember 1773 extending from an end of the first connection member 1731 inthe anterior-posterior direction. There are also two connection members173 each including the first connection member 1731 and the secondconnection member 1733 like the connection hole insertion members 171.

The ML member 175 extends from an end of the connection member 173 inthe medial-lateral direction. The ML member 175 includes an ML memberconnection means 1757 and an ML laser device 1759 combined with the MLmember connection means 1757.

The ML laser device 1759 emits a laser beam in a direction from a frontside 9131 of the distal end 913 of the femur 91 to the proximal end 911of the femur 91, to help the fixing portion 11 to be fixed at a correctposition. The laser beam travels along the front surface of the femur91, thereby preventing the fixing portion 11 from deviating, in a medialdirection or a lateral direction, from the mechanical axis of the femur91 and from being fixed in a misaligned state. The principles of thealignment are shown in FIG. 8 in detail. With reference to FIG. 8,alignment between the laser beam and the mechanical axis of the femur 91on the coronal plane can be easily verified.

The AP member 177 extends from an end of the ML member 175 in theanterior-posterior direction. The AP member 177 may include an AP memberconnection means 1771 and an AP laser device 1773 combined with the APmember connection means 1771.

The AP laser device 1773 emits a laser beam in a direction from one sidesurface of the distal end 913 of the femur 91 to the proximal end 911 ofthe femur 91, thereby helping the fixing portion 11 to be fixed at acorrect position. The laser beam travels along one side surface of thefemur 91, thereby preventing the fixing portion 11 from deviating in ananterior direction or a posterior direction, from the axis of the femur91. The principles of the alignment are shown in FIG. 7. With referenceto FIG. 7, since the laser beam travels along one side of the femur 91,it is possible to easily verify the alignment of the fixing portion withrespect to the femur 91 on the sagittal plane.

With reference to FIG. 9, the frontal cutting guide portion 13 is acomponent that guides cutting of the frontal end of the femur 91 and isfixed to the fixing portion 11 that is attached to the distal end 913 ofthe femur 91 after being aligned with respect to the fixing portion byusing the ML laser and the AP laser. The frontal cutting guide portion13 includes the first connection member 131 to be inserted into thefirst connection hole 113, a frontal cutting guide slot 133 for guidingcutting of the frontal end, and a second connection member 135 thatguides a position of a cutting saw within the frontal cutting guide slot133.

The first connection member 131 is inserted into the first connectionhole 113, thereby aligning and fixing the frontal cutting guide portion13 with the fixing portion 11 and at a correct position. There may betwo first connection members 131 to prevent axial rotation of thefrontal cutting guide portion 13.

The frontal cutting guide slot 133 is an elongated hole in which acutting device such as a cutting saw moves, thereby guiding the cuttingdevice that cuts away a front portion of the femur.

The second connection member 135 extends in the direction from thedistal end to the proximal end of the femur 91, and is inserted into afirst connection recess 151 of the distal cutting guide portion 15described below. The second connection member 135 connects the distalcutting guide portion 15 to the fixing portion 11 that is preliminarilyaligned by using a laser beam, thereby aligning the distal cutting guideportion 15.

The distal cutting guide portion 15 is a component that guides cuttingof the distal end 913 of the femur and is combined with the frontalcutting guide portion 13. The distal cutting guide portion 15 includesthe first connection recess 151, a distal cutting guide slot 153, and afrontal fixation hole 155.

The first connection recess 151 is an element into which the secondconnection member 135 is inserted such that the distal cutting guideportion 15 is automatically positioned at a correct position.

The distal cutting guide slot 153 is also an elongated hole in which acutting device such as a cutting saw moves to cut away a distal portionof the femur 91, like the frontal cutting guide slot 133.

The frontal fixation hole 155 is an element used to fix the distalcutting guide 15 to the frontal end of the tibia 93, and includes afrontal center fixation hole 1551 and a frontal inclined fixation hole1553.

The frontal center fixation hole 1551 is a portion into which a pin usedto fix the distal cutting guide portion 15 that is properly aligned isinserted before the frontal cutting guide portion 13, which is connectedto the fixing portion to resect the distal end 913 of the femur 91, isremoved. The frontal inclined fixation hole 1553 is an oblique holeinclined with respect to the anterior-posterior direction to securelyfix the distal cutting guide portion 15 at a specific position of thetibia 93 such that cutting of the tibia 93 is guided by the distalcutting guide portion 15. In order to securely fix the distal cuttingguide portion 15 from which the frontal cutting guide portion 13 isremoved to the front surface of the tibia 93, three or more pins need tobe inserted into the fixation holes including the frontal centerfixation hole and the frontal inclined fixation hole 1553.

With reference to FIGS. 10 and 11, the tibia resection device 3 includesthe tibia cutting guide portion 31 attached to the frontal end of thetibia 93 and a connector 33 attached to the tibia cutting guide portion31.

The tibia cutting guide portion 31 is a component that guides cutting ofthe proximal end 931 of the tibia 93. The tibia cutting guide portion 31includes a tibia fixation hole 311 used to fix the tibia cutting guideportion 31 to the tibia 93, a tibia cutting guide slot 313, and a guideportion rotation detection means 315.

The tibia fixation hole 311 is a hole provided to fix the tibia cuttingguide portion 31 to the tibia 93, and the tibia cutting guide portion 31preferably includes three or more tibia fixation holes 311.

Similarly with the frontal cutting guide slot 133, the tibia cuttingguide slot 313 is an elongated hole in which a cutting device, such as acutting saw, to resect the proximal end 931 of the tibia 93 is insertedto move in a predetermined direction.

The guide portion rotation detection means 315 is a component to measurea numerical value of an axial alignment state when the tibia cuttingguide portion 31 is fixed to the proximal end 931 of the tibia 93.Preferably, the guide portion rotation detection means 315 is a gyrosensor. The detection means 315 may further include a communicationdevice to communicate with an external display device so that a specificnumerical value of the rotation state of the tibia cutting guide portion31 can be checked from the external display device. When performing kneejoint replacement, since a surgical area is small, it is difficult for asurgeon to clearly observe the surgical area. However, when the surgicalarea is displayed on the external display device, a surgeon can clearlyand precisely observe and check the rotation state of the tibia cuttingguide portion and can easily and accurately align the cutting guideportion with a less burden. Due to the rotation detection meansdescribed above, when the tibia cutting guide portion 31 is alignedusing a laser and rotated for alignment, numerical verification ispossible. Furthermore, during the resection of the tibia following thealignment and fixation of the cutting guide portion, it is possible todetect rotation or twisting of the tibia cutting guide portion 31,thereby enabling an accurate resection. Since the guide portion rotationdetection means 315 needs to detect a relative rotation angle of thecutting guide portion with respect to the tibia 93, an additionalrotation detection means is preferably installed on the tibia 93.

The connector 33 is combined with the tibia cutting guide portion 31 andis equipped with a tibia laser device 3311 on one side surface thereof.

The tibia laser device 3311 assists a surgeon in positioning the tibiacutting guide portion 31 at a correct position when fixing the tibiacutting guide portion 31 to the tibia 93. With reference to FIG. 11, thetibia laser device 3311 is installed in front of the tibia 93 and emitsa laser beam toward the distal end 933 from the proximal end 931.Accordingly, the tibia laser device 3311 prevents the tibia cuttingguide portion 31 from rotating in a medial direction or a lateraldirection on the coronal plane and from being fixed at a wrong position.The principles of this alignment are shown in FIG. 10. With reference toFIG. 10, a surgeon rotates the tibia cutting guide portion 31 in themedial direction or the lateral direction while checking whether atravel direction of a laser beam is coincident with the axis of thetibia 93 until axis of the tibia becomes coincident with the traveldirection of the laser beam. In this way, the tibia cutting guideportion is properly aligned. Therefore, an axial alignment process iseasily performed in a short time, thereby reducing a burden to asurgeon, shortening an overall operation time, and helping recovery of apatient.

With reference to FIG. 14, the detector 8 is inserted between the distalend 913 of the femur 91 and the proximal end 931 of the tibia 93 todetect a rotation angle of an implant and a pressure applied to theimplant. The detector 8 is a thin plate having a shape similar to or thesame as that of the resected surface of the tibia 93. The detector 8 isprovided with a knob means 81, a positioning recess 83, an operationrotation detection means 85, a pressure detection means 87, and abattery 88.

The knob means 81 is formed at the outer periphery of the detector 8.Since the knob means 81 is formed to protrude from the outer peripheryof the detector 8, the detector 8 can be conveniently moved by holdingthe knob means 81 when the detector 8 is mounted on and removed from thebalance checker (refer to reference number 5 in FIG. 16) or a tibialcomponent trial (refer to reference number 73 in FIG. 17).

The positioning recess 83 is a recessed portion having a predetermineddepth and is provided in one surface of the detector 8. Preferably, thepositioning recess 83 is formed in a center portion of a lower surfaceof the detector 8. The positioning recess 83 is engaged with apositioning protrusion 7311 (described below) of the tibial componenttrial 83, thereby preventing the detector 8 from escaping when verifyingthe rotation and pressure of trials 7.

The operation rotation detection means 85 provided in or on one surfaceof the detector 8 detects a rotation state of the trial 7 and provides anumerical value of the rotation state. Preferably, the operationrotation detection means 85 is a gyro sensor and is equipped with acommunication device so that the numerical value of the rotation stateof the trial 7 can be checked using an external display device. Asurgical area in an actual knee joint replacement operation is verysmall, so it is difficult for a surgeon to clearly verify the rotationstate of the trial with eye. Therefore, the external display device isconnected to the detector 85 to clearly show the rotation state of thetrial. Therefore, a surgeon can easily perform an alignment between thebones and the surgical instrument with a less burden.

In addition, since the operation rotation detection means 85 needs todetect a relative rotation state of components of the surgicalinstrument with respect to the tibia 93 or the femur 91, the tibia 93 orthe tibial component trial 73 is mounted with a reference rotationdetection means serving as a reference position for detecting a rotationangle. Alternatively, the reference rotation detection means may bemounted on the femur 91 or the femoral component trial 71. Furtheralternatively, both the tibia (or the tibial component trial) and thefemur (or the femoral component trial) may be provided with respectivereference rotation detection means. This will be described in moredetail below.

When the detector 8 is inserted between the femur 91 and the 93, thepressure detection means 87 detects the force per unit area applied tothe femur 91 and the tibia 93 to obtain medial and lateral forcebalance. The pressure detection means may be a piezoelectric elementusing a piezoelectric effect, a strain gauge, a load cell, or the like.In this case, preferably, the detector may include a communicationdevice to communicate with an external display device, thereby enablinga surgeon to verify the pressure distribution using the external displaydevice, in the form of numerical numbers. Therefore, unlike aconventional art in which the medial and lateral force balance and thepressure distribution are checked depending on a surgeon's experienceand sensation, according to the present invention, a surgeon canprecisely verify the balance and pressure distribution with specificnumerical values displayed on the display device, so that a verificationburden to a surgeon is reduced and a precise, accurate, and fastoperation is possible.

The battery 88 is a power supply for the pressure detection means 87,the rotation detection means 85, and the communication device, and isprovided in a front portion of the detector 8 as shown in FIG. 14. Thebattery 88 may be removably mounted in the detector 8 or unitarilyembedded in the detector 8. In the case in which the battery 88 isremovably mounted, it is convenient in that the battery 88 can beseparately charged. This advantage will be described later.

With reference to FIGS. 12 to 16, the balance checker 5 is a componentto check balance between the distal end 913 of the femur 91 and theproximal end 931 of the tibia 93. The balance checker 5 includes aninsertion portion 51 and an extension 53 extending from the insertionportion 51.

As the insertion portion 51, there are two types respectively called afirst insertion portion 511 and a second insertion portion 513.

The first insertion portion 511 has a flat plate shape similar to theshape of the resected surface of the tibia 93 like the detector 8. Thefirst insertion portion 511 is slightly larger than the detector 8. Asthe first insertion portion 511, there may be two first insertionportions that are provided at respective ends of the extension 53. Withreference to FIG. 14, each first insertion portion 511 has anaccommodation recess 5111 in an upper surface thereof.

With reference to FIG. 14, the accommodation recess 5111 is a recessedportion having a predetermined depth and a shape corresponding to thedetector 8 to accommodate the detector 8. The first insertion portion511 is further provided with an outer recess 5111 a at one side of theaccommodation recess 5111 such that the knob means 81 of the detector 8can be received in the outer recess 5111 a when the detector 8 isaccommodated in the accommodation recess 5111 of the first insertionportion 511.

With reference to FIG. 15, the second insertion portion 513 is composedof an upper plate 5131 and a lower plate 5133 having a shape similar tothe shape of the resected surface of the tibia 93, and an insertion gap5135 is provided between the upper plate 5131 and the lower plate 5133.The insertion gap 5135 is a space into which the detector 8 is insertedto detect the pressure and the rotation angle. The detector 8 slidesinto the insertion gap 5135 when it is mounted. In the case ofinstalling the detector 8 in a sliding manner, it is not necessary tomount the detector 8 before installing the balance checker 5. That is,the balance checker 5 is first installed between the femoral componenttrial 71 and the tibia 93, and afterwards the detector 8 is insertedinto the balance checker 5. In this case, since the detector 8 has theknob means 81, the detector 81 can be easily inserted and removed. Foreasy installation and removal of the detector 8, the insertion gap 5135is deeply recessed in a position where the knob means 81 is located.Since the detector 8 needs to detect the pressure applied thereto in astate in which it is interposed between the upper plate 5131 an and thelower 5133, the upper plate 5131 and the lower plate 5133 are preferablymade of a soft material that can be slightly deformed when pressed.

The extension 53 is connected between the two insertion portions 51 andprovided with a checker laser device 531 at a middle portion thereof.

The checker laser device 531 is disposed in front of the tibia 93 whenthe insertion portion 51 is inserted between the femur 91 and the tibia93, and emits a laser beam in a direction from the proximal end 931 tothe distal end 933. The laser beam is used to check whether the balancechecker 5 including the insertion portion 51 is well aligned with thebone. This alignment checking process is shown in FIG. 13. Next, thealigned knee joint undergoes medial and lateral balance checking whilethe knee joint is extended (see FIG. 16) and flexed (see FIG. 12).

With reference to FIGS. 17 to 20, the trial 7 includes a femoralcomponent trial 71, a tibial component trial 73, and an insert trial 75.

The femoral component trial 71 is attached to the resected surface ofthe femur 91 and has the same shape as a femoral component serving as acartilage. As described above, the femoral component trial 71 mayinclude the reference rotation detection means 77.

The tibial component trial 73 is attached to the resected surface of theproximal end 931 of the tibia 93 and has the same shape as a tibialcomponent serving as a cartilage. The tibial component trial 73 mayinclude the positioning protrusion 7311 on an upper surface 731 thereof.The tibial component trial 73 may further include the reference rotationdetection means 77.

The positioning protrusion 7311 is engaged with the positioning recess(refer to reference number 83 in FIG. 18) of the detector 8, therebypreventing the detector 8 from being separated from the trial 7 when thepressure and rotation of the trial 7 is checked with the detector 8.

The insert trail 75 is disposed between the femoral component trial 71and the tibial component trial 73 and functions like a bearing. Theinsert trial 75 has an insert trial accommodation recess 751 in a lowersurface thereof.

The insert trial accommodation recess 751 is a cavity to accommodate thedetector 8. Therefore, the insert trial accommodation recess 751 has thesame shape as the contour of the detector 8. An outer recess 751 a isprovided at one side of the insert trial accommodation recess 751 sothat the knob means 81 of the detector 8 can be received in the outerrecess 751 a.

Next, a process of aligning a resection device for resecting a boneusing the surgical instrument S described above during artificial kneejoint replacement will be described.

With reference to FIGS. 5 to 9, the fixing portion 11 is attached to thedistal end 913 of the femur 91. Next, the fixing portion fixing means112 is inserted into the distal center fixation hole 1111 for temporaryfixation.

Next, the connecting portion 17 is connected to the fixing portion 11 byinserting the connection hole insertion member 171 of the connectingportion 17 into the first connection hole 113 of the fixing portion 11.The ML laser device 1758 combined with the connecting portion 17 guidesmedial-lateral alignment on the coronal plane as illustrated in FIG. 7,and the AP laser device 1773 guides anterior-posterior alignment on thesagittal plane as illustrated in FIG. 8. At this time, the fixingportion rotation detection means 117 detects a rotation angle of thefixing portion 11 with respect to the femur 91 and displays the rotationangle on the external display device. A surgeon adjusts the rotationangle of the fixing portion 11 while checking the rotation angledisplayed on the display device. Therefore, a precise and accurateoperation is possible and a burden to a surgeon for verification ofrotation of the fixing portion is reduced.

After the position adjustment of the fixing portion 11 is finished,another fixing portion fixing means 112 is inserted into the distallopsided elongated hole 1113. Since the distal lopsided elongated hole1113 is a long hole extending in a vertical direction, even when thefixing portion fixing means 112 are respectively inserted into thedistal center fixation hole 1111 and the distal lopsided elongated hole1113, the fixing portion 11 can be slightly rotated. When the positionof the fixing portion 11 is finally determined after the rotation of thefixing portion 11 is finely adjusted, a further fixing portion fixingmeans 1114 is inserted into the distal lopsided fixation hole 1114, sothat the fixing portion 11 is securely fixed not to be displaced. Sincethe fixing portion 11 is fixed by the three fixing portion fixing means,the fixing portion 11 can be securely fixed. The finished state of thisprocess is shown in FIG. 9.

Next, with reference to FIG. 9, the connecting portion 17 is removed,and the first connection member 131 of the frontal cutting guide portion13 is engaged with the first connection hole 113. Next, a cutting devicesuch as a cutting saw is inserted into the frontal cutting guide slot133 to resect a front portion of the femur. At this time, the fixingportion rotation detection means 117 detects whether the frontal cuttingguide portion 13 combined with the fixing portion 11 is rotated by theforce attributable of motion of the cutting device.

Next, the position of the distal cutting guide portion 15 is determinedby inserting the second connection member 135 into the first connectionrecess 151 of the distal cutting guide portion 15. Next, fixing meanssuch as pins are inserted into the frontal center fixation hole 1551 andthe frontal inclined fixation hole 1553 such that the distal cuttingguide portion 15 is fixed to the front side of the femur 91, and thefrontal cutting guide portion 13 is removed. Finally, a cutting devicesuch as a cutting saw is inserted into the distal cutting guide slot 153and the distal end 913 of the femur 91 is resected by using the cuttingdevice.

In the process described above, the frontal portion is resected firstand then the distal portion is resected. However, this sequence is onlyexemplary and can be changed. That is, the distal portion 913 may beresected first, and then the frontal portion may be resected.

With reference to FIGS. 10 to 11, the tibia cutting guide portion 31 isattached to the front side of the tibia 93 to resect the tibia 93. Afixing pin is first inserted into the tibia center fixation hole 3111for temporary fixation of the tibia cutting guide portion 31, theconnector 33 is attached to the tibia cutting guide portion 31, andmedial-lateral alignment on the coronal plane can be performed using alaser beam emitted by the tibia laser device 3311. When the tibiacutting guide portion 31 is rotated while checking whether the axis ofthe tibia 93 is coincident with the laser beam, the guide portionrotation detection means 315 detects and sends a relative rotation angleof the tibia cutting guide portion with respect to the tibia 93 to theexternal display device. Therefore, a surgeon can rotate the tibiacutting guide portion 31 while checking the relative rotation angle fromthe external display device. Therefore, a precise and accurate surgicaloperation can be performed and a burden to a surgeon is reduced.

After the alignment of the tibia cutting guide portion is finished, apin is inserted into the tibia inclined fixation hole 3113 to securelyfix the tibia cutting guide portion 31 to the tibia. Preferably, threeor more pins may be used. Next, a cutting device such as a cutting sawis inserted into the tibia cutting guide slot 313 to resect the proximalend 931 of the tibia 93. The operation rotation detection means 315detects and sends a relative rotation angle of the tibia cutting guideportion to the external display device. Therefore, it is possible tocheck whether the tibia cutting guide portion 31 is displaced by theforce attributable to motion of the cutting device.

With reference to FIGS. 12 to 16, the femoral component trial 71 isattached to the resected surface of the femur 91, and the insertionportion 51 of the balance checker 5 mounted with the detector 8 isinserted between the tibia 93 and the femoral component trial 71. In thecase in which the second insertion portion 513 is provided in thebalance checker 5, the detector 8 can be inserted into the balancerchecker 5 in a sliding manner.

The checker laser device 531 emits a laser beam from the front side ofthe tibia 93 toward the distal end. Therefore, it is possible to checkwhether the balance checker 5 is aligned with the axis of the tibiausing the laser beam.

Next, the knee joint is extended (see FIG. 16) and flexed (see FIG. 12)and the medial and lateral balance is verified. At this time, since theoperation rotation detection means 85 included in the detector 8 detectsa relative rotation angle of the balance checker 5 with respect to thefemoral component trial 71, a precise adjustment can be performed whilechecking numerical values, and thus balance verification can be reliablyperformed.

In addition, the rotation and balance between the femur 91 and the tibia93 can be easily verified using the pressure detection means 87. Theterm ‘balance’ may mean a difference in force distribution between amedial side and a lateral side of the knee joint, or a difference inforce distribution between the case of extension and the case of flexionof the knee joint. When the difference in force distribution is large,the resection amount of the medial side, the lateral side, the distalside 913, or a rear side of the femur 91 is adjusted to obtain a desiredbalance state.

The pressure detection means 87 detects the distribution of pressure anddisplays it on an external display device. Therefore, a surgeon caneasily and quickly perform an accurate surgical operation by checkingthe balance from the display device.

With reference to FIGS. 17 to 20, after the femoral component trial 71is attached to the resected surface of the femur 91 and the tibialcomponent trial 73 is attached to the resected surface of the tibia 93,the insert trial 75 equipped with the detector 8 that is accommodated inthe accommodation recess 751 is inserted between the femoral componenttrial and the tibial component trial. Next, the balance is verifiedwhile extending and flexing the knee joint. At this point, the operationrotation detection means 85 included in the detector 8 detects arotation angle of the insert trial 75 with respect to the femoralcomponent trial 71. Therefore, it is possible to precisely adjust therotation angle through numerical verification, thereby accurately andreliably verifying the balance.

In addition, it is possible to easily numerically verify the pressuredistribution in accordance with rotation angles by using the pressuredetection means 87. Herein, the balance may mean a difference in forcedistribution between a medial side and a lateral side of the knee joint,or a difference of force distribution between the case of extension andthe case of flexion of the knee joint. When the difference in forcedistribution is large, the trial 7 is replaced with a larger size trialor an insertion angle of the trial is changed to obtain a suitablebalance state.

As described above, since the pressure detection means 87 detects andsends a pressure distribution to the external display device, a surgeoncan verify the balance using the information displayed on the externaldisplay device, so that the surgeon can easily perform a fast, precise,and accurate operation.

With reference to FIGS. 21 and 22, the battery 88 can be charged usingan additional charging means 2. In this case, the charging means 2transfers electric charges to the battery 88 in a wireless manner.Specifically, when the battery 88 is placed on the charging means 2, thebattery is charged by radio frequency.

When the battery 88 is detachably mounted in the detector 8, asillustrated in FIG. 22, only the battery 88 can be placed on thecharging means 2. However, when the battery 88 is embedded in thedetector 8, as illustrated in FIG. 21, the whole detector 8 mounted withbattery 88 is placed on the charging means 2 for charging of the battery88.

The detailed description above is about an exemplary embodiment of thepresent invention. Although preferred embodiments of the presentinvention have been described for illustrative purposes, those skilledin the art will appreciate that various combinations, changes, andapplications thereof are possible. The preferred embodiments can bechanged or modified within the scope of the concept of the inventiondisclosed in the specification, the scope of equivalents, and/or therange of technologies or knowledge of those skilled in the art. Thepreferred embodiments that have been described above are best modes torealize the technical spirit of the present invention, and diversechanges required in application and use of the invention are alsopossible. In consequence, the detailed description is not intended tolimit the scope of the invention but the scope of the following claimsshould be construed as including other embodiments.

What is claimed is:
 1. A smart surgical instrument for artificial jointreplacement, the surgical instrument comprising a tibia resection devicefor resecting a tibia, wherein the tibia resection device comprises alaser device, whereby the surgical instrument enables an easy and fastsurgical operation by eliminating a need of using an extramedullaryaligner during alignment of the tibia for resection of the tibia.
 2. Thesurgical instrument according to claim 1, wherein the tibia resectiondevice comprises a tibia cutting guide portion attached to a frontal endof the tibia and a connector combined with the tibia cutting guideportion, and the laser device is mounted on the connector to emit alaser beam to a distal end of the tibia, whereby the surgical instrumentfacilitates alignment of the tibia cutting guide portion.
 3. Thesurgical instrument according to claim 2, wherein the tibia cuttingguide portion comprises a rotation detection means, thereby enablingnumerical verification for an alignment state of the tibia cutting guideportion when the tibia cutting guide portion is aligned with a laserbeam, whereby the surgical instrument enables precise, accurate, easy,and fast alignment of the tibia cutting guide portion.
 4. The surgicalinstrument according to claim 3, wherein the rotation detection means isa gyro sensor.
 5. The surgical instrument according to claim 4, whereinthe rotation detection means comprises a communication device tocommunicate with an external display device so that a specific numericalvalue of the rotation state of the tibia cutting guide portion can bechecked from the external display device.
 6. The surgical instrumentaccording to claim 3, the tibia cutting guide portion comprising a tibiacutting guide slot.
 7. The surgical instrument according to claim 6,wherein the tibia cutting guide slot is approximately perpendicular tothe laser emission direction of the laser device.